July 23, 2014 (MELBOURNE, Australia) -- Five groups of people are driving the global HIV epidemic, the World Health Organization (WHO) says in its new guidelines.

Men who have sex with men, sex workers, injection-drug users, transgender people, and people in prisons are among the groups targeted for prevention and treatment efforts.

HIV rates are "going down all over the world, with the exception of key affected populations," Fabio Mesquita, MD, said during a news conference at the 20th International AIDS Conference. Mesquita is the director of the HIV and viral hepatitis program at the Ministry of Health in Sao Paulo, Brazil.

"If we don't address key affected populations, we won't reach our goal of controlling the epidemic by the year 2030," he said.

Recent statistics indicate that men who have sex with men are up to 19 times more likely than people in the general population to be infected with HIV. Female sex workers are up to 14 times more likely to be infected. Transgender women are almost 50 times more likely to be infected.

"In all parts of the world, these populations have compromised access to good [HIV-related] services," said Gottfried Hirnschall, MD, director of the WHO Department of HIV/AIDS.

'Hostile Environment' for People at High Risk

Laws that stigmatize people and penalize sexual orientation drive risky behavior underground, making it hard, if not impossible, for people at high risk for HIV to access HIV prevention and care services, speakers at the news conference explained.

As a consequence of this hostile environment, rates of new HIV infections are increasing in all these groups, but especially in men who have sex with men, a group in which "explosive epidemics" of HIV are occurring in many parts of the world, Hirnschall said.

It's estimated that up to 50% of all new HIV infections occur in these groups, according to the Joint United Nations Programme on HIV/AIDS.

Guideline Recommendations

One of the major recommendations in the guidelines is that an HIV-prevention method called pre-exposure prophylaxis, or PrEP, be part of prevention efforts for men who have sex with men. PrEP involves taking a daily pill containing two medicines, and it can help protect an uninfected person against HIV -- although it's not 100% effective.

"There is strong evidence for this recommendation," said guideline chair Chris Beyrer, MD. He's the director of the Johns Hopkins Center for Public Health and Human Rights in Baltimore, and president-elect of the International AIDS Society.

Beyrer stressed, though, that PrEP treatment is not recommended for all men who have sex with men -- only those who want the treatment and who are at risk for HIV. He explained that PrEP must be used with other prevention methods, such as condoms, condom-appropriate lubricant, and education.

The recommendation to consider PrEP an option for HIV prevention in men who have sex with men is both "valuable and important," said Robert Grant, MD, MPH. He's a professor of medicine at the University of California, San Francisco. Grant was involved in a study that showed that PrEP provides a high degree of protection against HIV infection, even if someone didn't take the medicine exactly as prescribed.

"I think the WHO recommendation reflects the high-quality evidence that PrEP provides protection for men who have sex with men," Grant said.

He cautioned, though, that people do go through "seasons of risk," and they might stop treatment if they no longer feel they need PrEP for HIV protection.

The other major recommendation is to make the medication naloxone available in the community to reverse an overdose. People likely to witness an opioid overdose should have access to naloxone and be taught how to use it in case of an emergency, the guidelines say.

Overdose Deaths and HIV

"We know that, worldwide, 69,000 individuals die from heroin or opioid overdose each year," said Phillip Read, MD. He's the medical unit manager at the Kirketon Road Centre in Sydney, Australia. "In fact, HIV-positive people who inject [opioids] and who are on treatment have a greater risk of dying from an overdose than from HIV." Also, about 60% of overdose deaths occur in the presence of someone else.

Naloxone rapidly reverses the toxic effects of heroin and some opioids, such as oxycodone. It can be given by injections or sprayed directly into the nostrils in aerosol form.

In a pilot project of people dependent on opioids, Australian investigators found that almost all people in their study had witnessed an overdose, and almost two-thirds had overdosed themselves. There is a "real opportunity" to intervene, Read said.

When the Australian group gave the study participants a supply of naloxone, about 20% used it to reverse an overdose within a year, Read told Medscape Medical News.

The recommendation from previous guidelines that people who inject drugs have access to sterile injecting equipment through needle-and-syringe programs remains.

"The importance of these programs in blood-borne virus prevention in people who inject cannot be overstated," Read said.

In Australia, a comprehensive needle-and-syringe program has been in place since the late 1980s. As a result, the prevalence of HIV in heterosexual people who inject drugs is below 1%.

It's been estimated that, since its inception, the needle-and-syringe program has prevented more than 50,000 new cases of HIV in Australia, and more than 100,000 cases of hepatitis C.

"We know that for every dollar spent on needle-and-syringe programs, over $4 is returned to the state in direct cost savings," Dr. Read said. "These programs are not only ethically and medically important, they are economically important as well."

The guidelines also recommend that all people from the groups at high risk for HIV who are dependent on opioids continue to have access to medicines that are substitutes for the opioids and control the addiction.